On 2/2/2024 10:30 AM, Amrit Anand wrote:
<snip>
There's a similar issue for EFI boot with how to select an OS installed
DTB[1]. You might not care now, but users may later on (like we have
already with QCom devices with fixed bootloaders). If you do this
board-id route, then no doubt that compatible values won't be specific
enough or have suitable fallbacks to be used. Then EFI boot can't use
compatible either and needs to use this QCom specific logic. It may be a
common property name, but all the types you defined are QCom specific
and the matching logic is pretty much undocumented. I'm not saying we
have to use compatible. There wasn't even agreement to use it for EFI
boot case. This does need to work for multiple vendors and multiple boot
scenarios.
Agree, given so many hardware identifiers Qcom uses to find the DT
based on a best and exact match algorithm, it may not work as is for
other vendors/users outside the scope of Qcom.
Since we have none to very limited visibility into complete set of DT
selection identifiers being used by other users or into their
selection algorithms since it is mostly undocumented,
designing a perfectly generic solution (one-size-fits-all) could be
far-fetched. The number of board files in Qcom DT selection software
package often reaches over 100 DT files due to multiple SoCs and
board types being supported out of a single software package and these
multiple hardware identifiers helps to pick the closest best match DT
within a very large pool of DTs.
Not to affect other users/vendors who would be using their own set of
identifiers and an entirely different algorithm for DT selection,
would it make more sense to define these Qcom specific
identifiers within Qcom specific bindings (qcom.yaml), along with
detailed documentation on our DT selection algorithm?
I have written a patch for defining Qcom specific identifiers within
Qcom specific bindings (qcom.yaml) along with documentation on DT
selection algorithm, would it be okay to send for review?
Thanks,
Amrit
Rob
[1] https://lore.kernel.org/u-boot/20231114232012.GD6601@bill-the-cat/#r
